Sheet media stack imaging system

ABSTRACT

An imaging system that includes a sheet media stack over a recording unit. Image data is generated in response to radiation received from a field of view encompassing sheet media edges of individual media within the sheet media stack. Edges of individual media are detected within the image data.

CROSS REFERENCE TO RELATED APPLICATIONS

This present disclosure is a continuation of U.S. application Ser. No.11/356,633, filed on Feb. 17, 2006. The contents of which is herebyincorporated by reference in its entirety.

The present application contains subject matter related to U.S.application Ser. No. 11/252,085 (now U.S. Pat. No. 7,490,828), filed onOct. 17, 2005. The subject matter thereof is hereby incorporated hereinby reference thereto.

BACKGROUND ART

The present invention relates generally to an imaging system, and moreparticularly to a sheet media stack imaging system.

Drawings, marks, words, pictures, sketches, diagrams, and the like areformed every day around the world by humans to communicate ideas, andeven though we live in a technically advanced computer savvy society,pen to paper is the oldest and most natural solution for capturing thisinformation quickly. Unfortunately, notations on paper are not readilyconverted to digital format and normally require a time consumingscanning operation.

Digital notepads are one way of seamlessly integrating paper notationsinto a digital format. A digital notepad, also known as a digitizer pad,is a computer-input device, which captures graphical user inputs,including handwriting, impressed upon a surface of a pad and convertsthat user input into a digital representation thereof.

A typical digital notepad may include paper overlying a pressuresensitive element and a pen-like writing stylus. The stylus or specialpen includes both an ink system for writing on the paper and anelectronic circuit for interacting with the electronic pressuresensitive elements located within the pad. Digital notepads are used incomputer aided drafting (CAD) applications, to record signature imagesin electronic commerce, and in certain biometrics applications.

Unfortunately, current digital notepad technology does not possesspage-to-page correlation capability. Consequently, a user needs tomanually define what page they are working on by striking a soft key onthe digitizer pad surface or by pressing a button on the digitalnotepad. Without such manual operation by the user, subsequent writingformed after removal of a paper sheet will over scribble notationsformed on the digitizer pad for the previous page.

Thus, a need still remains for a digital notepad with automatic pagetracking capability that prevents overwriting notations formed on aprevious page. In view of the ever-increasing need to save costs andimprove efficiencies, it is more and more critical that answers be foundto these problems.

Solutions to these problems have been long sought but prior developmentshave not taught or suggested any solutions and, thus, solutions to theseproblems have long eluded those skilled in the art.

DISCLOSURE OF THE INVENTION

The present invention provides a sheet media stack over a recordingunit. Image data is generated in response to radiation received from afield of view encompassing sheet media edges of individual media withinthe sheet media stack. Edges of individual media are detected within theimage data.

Certain embodiments of the invention have other advantages in additionto or in place of those mentioned above. The advantages will becomeapparent to those skilled in the art from a reading of the followingdetailed description when taken with reference to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of an imaging system including a portion of asheet media stack in accordance with an embodiment of the presentinvention;

FIG. 2 is an exemplary graph of pixel intensity values of image data inaccordance with an embodiment of the present invention;

FIG. 3 is an image of the sheet media edges in accordance with anembodiment of the present invention;

FIG. 4 is a digital notepad with an imaging system in accordance with anembodiment of the present invention;

FIG. 5 is a top view of the imaging system with a top portion removedfor purposes of clarity in accordance with an embodiment of the presentinvention;

FIG. 6 is a top view of the imaging system with a top portion removedfor purposes of clarity in accordance with another embodiment of thepresent invention; and

FIG. 7 is a flow chart for an imaging system for fabricating the imagingsystem in accordance with an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The following embodiments are described in sufficient detail to enablethose skilled in the art to make and use the invention, and it is to beunderstood that other embodiments would be evident based on the presentdisclosure and that process or mechanical changes may be made withoutdeparting from the scope of the present invention.

In the following description, numerous specific details are given toprovide a thorough understanding of the invention. However, it will beapparent that the invention may be practiced without these specificdetails. In order to avoid obscuring the present invention, somewell-known system configurations, and process steps are not disclosed indetail. Likewise, the drawings showing embodiments of the invention aresemi-diagrammatic and not to scale and, particularly, some of thedimensions are for the clarity of presentation and are shown exaggeratedin the drawing FIGs. In addition, where multiple embodiments aredisclosed and described having some features in common, for clarity andease of illustration, description, and comprehension thereof, similarand like features one to another will ordinarily be described with likereference numerals.

The term “horizontal” as used herein is defined as a plane parallel tothe plane or surface of a digital notepad, regardless of itsorientation. The term “vertical” refers to a direction perpendicular tothe horizontal as just defined. Terms, such as “on”, “above”, “below”,“bottom”, “top”, “side” (as in “sidewall”), “higher”, “lower”, “upper”,“over”, and “under”, are defined with respect to the horizontal plane.

Referring now to FIG. 1 therein is shown a sectional view of an imagingsystem 100 including a portion of a sheet media stack 102 in accordancewith an embodiment of the present invention. In this embodiment, animage sensor 104, such as a sheet media sensor, is incorporated in ahousing 106 of the imaging system 100. The image sensor 104 containslogic circuitry for performing complex computations. The housing 106supports a lens 108, which directs radiation reflected from sheet mediaedges 110 to an active area of the image sensor 104. The image sensor104 and a radiation source 112 are mounted on a substrate 114. In theillustrated embodiment, the substrate 114 is an interconnectionsubstrate, such as a printed circuit board.

The sheet media stack 102 overlies a sheet media support 118 and mayinclude paper media, such as a notepad bound together along one edge,possibly but not limited to the top edge, or plastic media, such astransparencies. The sheet media support 118, such as a recording unit,documents notations formed on the sheet media stack 102 either by apressure sensitive mechanism or an electrically sensitive mechanism. Byway of example and not by way of limitation, the sheet media support 118may include a digital notepad, a capacitive system, an electromagneticsystem, an ultrasonic system, an infrared system, a laser scan system,or an optical patterned paper system.

The image sensor 104 and the radiation source 112 are electricallyconnected to the substrate 114 by electrical conductors 116. Theradiation source 112 illuminates the sheet media edges 110 and thereflected radiation passes through the lens 108 along an optical axisthat intersects the sheet media stack 102 plane that is defined by thesheet media edges 110. By way of example, the radiation source 112 mayilluminate the edges of the sheet media stack 102 in a vertical manner.However, in accordance with the scope of this invention, the radiationsource 112 may illuminate the sheet media edges 110 from any angle,whether oblique or acute to the sheet stacking direction, which enhancesthe contrast between the edges of the sheet media stack 102.

The image sensor 104 generates image data in response to light receivedfrom a field of view 120 through the lens 108 that encompasses the sheetmedia edges 110 of ones of the sheet media stack 102. The image sensor104 may be any type of sensor, including a charge coupled device (CCD)sensor or a complementary metal-oxide-semiconductor (CMOS) sensor. Thelens 108 may include one or more lenses that focus radiation that isreflected from the edges of the sheet media stack 102 onto the imagesensor 104. The edges of the sheet media stack 102 may be illuminated byambient light or by the radiation source 112 (e.g., a light emittingdiode or a laser diode).

The field of view 120 of the image sensor 104 may encompass any numberof sheet media that is desired by the user. In some implementations, thefield of view 120 extends vertically from the bottom sheet level up to aview level that is at least as high as the specified maximum sheet mediacapacity level of the imaging system 100. In other implementations, thefield of view 120 extends vertically from the bottom sheet level up toany view level that is lower than the specified maximum sheet mediacapacity level of the imaging system 100. The field of view 120 of theimage sensor 104 is currently only limited by the technology of imagesensing equipment.

As an exemplary illustration, the field of view 120 of the image sensor104 may accommodate an engineering pad of paper with 60 micrometer sheetthickness and 200 sheets. Thus, the image sensor 104 having the field ofview 120 that is 12 millimeters or larger is enough to image such amedia stack. Ideally, the image sensor 104 should devote at least 5pixels for imaging each sheet, therefore, almost any high volume lowcost 1.3M pixel commercial image sensor with 1280×1024 resolution canimage such a media stack.

The logic circuitry located within the image sensor 104 detects edges ofindividual ones of the sheet media in the image data that is generatedby the image sensor. The logic circuitry may be implemented by one ormore discrete modules that are not limited to any particular hardware orsoftware configuration and may be implemented in any computing orprocessing environment, including in digital electronic circuitry (e.g.,application specific integrated circuits) or in computer hardware,firmware, device driver, or software.

The logic circuitry may detect the edges of the sheet media in the imagedata in any of a wide variety of different ways. In some embodiments,the logic circuitry averages the image data corresponding to pixels ofthe image sensor 104 that are parallel to the edges of the sheet media(i.e. —orthogonal to the sheet stacking direction). The logic circuitryfilters the averaged image data through a low-pass filter to reducenoise. The logic circuitry then applies a threshold to the filteredimage data to detect peaks in the filtered image data.

Referring now to FIG. 2, therein is shown an exemplary graph of pixelintensity values (I_(ave)) of image data in accordance with anembodiment of the present invention. The image data represented in FIG.2 has been low-pass filtered and averaged in the direction orthogonal tothe sheet stacking direction. The filtered and averaged pixel values areplotted as a function of vertical distance along the sheet stackingdirection from the bottom of the field of view 120, which typicallycorresponds to the top surface of the sheet media support 118. Theexemplary threshold (I_(th)) is selected to distinguish the pixel valuescorresponding to the edges of the sheet media from the pixel valuesgenerated from light received from below the stack (e.g., area 202),pixel values generated from light received from above the stack (e.g.,area 204), and pixel values generated from light received from betweenthe sheets (e.g., depression 206).

In general, the logic circuitry may perform a wide variety of statusmonitoring functions based on the detected edges of the sheet media inthe image data.

For example, in some embodiments, the logic circuitry counts the numberof peaks 208 in the graph of the image data to determine the number ofsheet media within the field of view 120. Yet still, in otherembodiments, the logic circuitry may count the number of the peaks 208in the graph of the image data, and subtracts this number from theoriginal number/value of sheets when the user input began, therebydetermining the number of media sheets used. By employing these methods,the present invention can automatically track the user media page numberand prevent over scribble of a previous page when the user begins inputon a new media page. Furthermore, the imaging system 100 displaysautomatic page tracking capability even when the user is flipping pagesback-and-forth, as one might when jotting down notes.

Referring now to FIG. 3, therein is shown an image 300 of the sheetmedia edges 110 in accordance with an embodiment of the presentinvention. As seen from the image 300, ten (10) individual sheet mediacan be distinguished. This image data is then sent to the logiccircuitry for additional filtering to enhance the contrast and count theexact number of sheet media over the sheet media support 118 (notshown).

Referring now to FIG. 4, therein is shown a digital notepad 400 with theimaging system 100 in accordance with an embodiment of the presentinvention. The digital notepad 400 includes the imaging system 100, theradiation source 112, a digital pen 402, a control panel 404, a menuselection key 406, an insert slot 408, a digital pen holder 410, a datainput/output port 412, and a battery holder 414.

The digital notepad 400 is able to digitally capture writing/drawingstrokes made by an associated stylus, such as the digital pen 402, atvarying distances from the digital notepad 400 surface, which is thecase as sheets of media are inked and removed from the digital notepad400. The digital pen 402 may contain an electromagnetic transmitter,which is tracked by the digital notepad 400. The digital pen 402 mayalso be equipped with a pressure-sensitive mechanical sensor or othertype of contact sensor, for detecting when the tip of the digital pen402 is in contact with the sheets of media.

When the digital pen 402 is in contact with the sheets of media, asignal is transmitted from the digital pen 402 in any manner suitable toindicate its position of contact with the digital notepad 400. Thedigital notepad 400 in turn generates data indicating the position ofthe digital pen 402, and whether the tip of the digital pen 402 is incontact with the sheets of media.

While the digital notepad 400 is described with reference to anelectromagnetic digitizer pad, it will be understood that the digitalnotepad 400 is not limited to that particular type, but may be any typeof device having the ability to digitally capture writing/drawingstrokes. For example, if the digital notepad 400 is responsive topressure (resistivity), the pen need be no more than an ordinary passivepen or pencil. When the digital notepad 400 uses laser tracking, thedigital pen 402 is provided with a suitable target material at the tip.Ultrasonic tracking may also be used. The digital pen 402 may also beequipped with a spatial sensing system using accelerometers to track thepen's position and an RF transmitter to communicate the positioninformation in real time to a receiver in the digital notepad 400.

Also, as is known but not illustrated, the digital notepad 400 may haveits own processor, memory and input/output (I/O) devices capable ofimplementing one or more of the operations described herein. It is to beunderstood that the term “processor” as used herein is intended toinclude any processing device, such as, for example, one that includes aCPU (central processing unit) and/or other processing circuitry. Theterm “memory” as used herein is intended to include memory associatedwith a processor or CPU, such as, for example, RAM, ROM, a fixed memorydevice (e.g., hard drive), a removable memory device, flash memory, etc.In addition, the term “input/output devices” or “I/O devices” as usedherein is intended to include, for example, one or more input devices,e.g., keyboard, pen or stylus, for entering data to the processing unit,and/or one or more output devices, e.g., CRT or other display, speakerand/or printer, for presenting results associated with the processingunit.

Additionally, it is also to be understood that the term “processor” mayrefer to more than one processing device and that various elementsassociated with a processing device may be shared by other processingdevices. Accordingly, software components including instructions or codefor performing the methodologies of the invention, as described herein,may be stored in one or more of the associated memory devices (e.g.,ROM, fixed or removable memory) and, when ready to be utilized, loadedin part or in whole (e.g., into RAM) and executed by a CPU.

The digital notepad 400 includes the imaging system 100, which can berecessed within the digital notepad 400 when not in use. The imagingsystem 100 includes the image sensor 104 (not shown), with itscorresponding logic circuitry, and the lens 108 (not shown). As notedbefore, the imaging system 100 captures image data received from theedges of the individual sheet media located over the surface of thedigital notepad 400. Additionally, when deployed or recessed, theimaging system 100 may act as a power ON/OFF switch for the digitalnotepad 400.

Although the imaging system 100 is depicted on one side of the digitalnotepad 400, it is not to be limited to such a position. The imagingsystem 100 may be located on any side of the digital notepad thatfacilitates the capturing of image data. Furthermore, the presentinvention includes the use of more than one of the imaging systems 100,wherein the image data received from each of the imaging systems 100 iscorrelated to produce a more accurate count of the sheet media locatedover the digital notepad 400.

The digital notepad 400 also includes the radiation source 112. As anexemplary illustration, the radiation source 112 may be recessed withinthe plane of the digital notepad and illuminate the edges of the sheetsof media in a vertical direction. However, in accordance with the scopeof this invention, the radiation source 112 may illuminate the edges ofthe sheets of media from any angle, whether oblique or acute to thesheet stacking direction, which enhances the contrast between the edgesof the sheet media.

The digital notepad 400 also includes the control panel 404, which candisplay a plethora of user-defined options. For example, a user may viewthe current page number, pen color choice, date, time, and/or a previewof a digital note.

Additionally, the menu selection key 406 allows for navigation withinthe functions offered by the digital notepad 400. For example, the menuselection key 406 may contain a reset function or reset button optionfor when user input is complete. The reset function/button will allowthe user to reset a counter within the logic circuitry to a currentvalue equal to the number of media sheets located over the digitalnotepad 400 when the user input is complete for that job or task (i.e.—the original value). By resetting the counter to the original value,the imaging system 100 can count the number of sheets used in the nextjob or task and automatically advance the digital notepad 400 to thenext page when a page is removed from the media stack.

The menu selection key 406 may also permit a user to designate the typeof interface option for the digital notepad 400. For example, thedigital notepad 400 may interface with other systems by a uniform serialbus (USB) connection, a wireless fidelity connection, an infraredconnection or a Bluetooth™ connection.

The digital notepad 400 also contains an insert slot 408. As anexemplary illustration, the insert slot 408 can be designed forreceiving the cardboard backing of a paper pad, such as an engineeringpad; however, it is not to be limited to such a use. In accordance withthe invention, the insert slot 408 may accommodate any structure usedfor support by the media stack, or any structure that helps to securethe media stack to the digital notepad 400, thereby preventing slippageof the media stack during user input.

Additionally, as is known within the art, the digital notepad 400includes the data input/output port 412. The data input/output port 412may accommodate any data transmission process, such as but not limitedto, serial, USB or infrared.

Referring now to FIG. 5, therein is shown a top view of the imagingsystem 100 with a top portion removed for purposes of clarity inaccordance with an embodiment of the present invention. The imagingsystem 100, which houses the image sensor 104 and the lens 108, issquare in shape, and consequently, the image sensor 104 and the lens 108must be positioned accordingly to view the sheet media stack 102. Theimage sensor 104 and the lens 108 may be positioned to view the sheetmedia stack 102 at any angle that produces optimal image data. Byaligning the image sensor 104 and the lens 108 at an angle to the planeof the sheet media edges 110, the depth of focus can be increased andthe clarity of the image data can be enhanced.

Referring now to FIG. 6, therein is shown a top view of the imagingsystem 100 with a top portion removed for purposes of clarity inaccordance with another embodiment of the present invention. The imagingsystem 100, which houses the image sensor 104 and the lens 108, istriangular in shape. Advantageously, the triangular housing structurecan provide a larger area to view the sheet media edges 110. The imagesensor 104 and the lens 108 may be positioned to view the sheet mediastack 102 at any angle that produces optimal image data.

Referring now to FIG. 7, therein is shown a flow chart for an imagingsystem 700 for fabricating the imaging system 100 in accordance with anembodiment of the present invention. The imaging system 100 includesproviding a sheet media stack over a recording unit in a block 702;generating image data in response to radiation received from a field ofview encompassing sheet media edges of individual media within the sheetmedia stack in a block 704; and detecting edges of individual mediawithin the image data in a block 706.

It has been discovered that the present invention thus has numerousadvantages. A principle advantage is automatic page tracking capabilityfor digital notepad technology that prevents overwriting notationsformed on a previous page. This feature prevents loss of data from overscribbling, which can increase the productivity of a user.

Another advantage of the present invention is that a user no longerneeds to manually input a page number change. This advantage offers easeof use, which can also increase the productivity of a user.

Yet still, another advantage of the present invention is that a user canreadily flip back-and-forth between pages without fear of over writing aprior notation on a previous page. This advantage offers ease of use bypreventing loss of an inventive concept due to time consuming steps,such as appropriate page number designation.

These and other valuable aspects of the present invention consequentlyfurther the state of the technology to at least the next level.

Thus, it has been discovered that the imaging system of the presentinvention furnishes important and heretofore unknown and unavailablesolutions, capabilities, and functional advantages. For instance, theimaging system of the present invention permits automatic page trackingcapability for digital notepad technology, which prevents overwritingnotations formed on a previous page. The resulting processes andconfigurations are straightforward, cost-effective, uncomplicated,highly versatile and effective, can be implemented by adapting knowntechnologies, and are thus readily suited for efficient and economicalmanufacturing.

While the invention has been described in conjunction with a specificbest mode, it is to be understood that many alternatives, modifications,and variations will be apparent to those skilled in the art in light ofthe aforegoing description. Accordingly, it is intended to embrace allsuch alternatives, modifications, and variations which fall within thescope of the included claims. All matters hithertofore set forth hereinor shown in the accompanying drawings are to be interpreted in anillustrative and non-limiting sense.

1. An imaging system comprising: a sheet media stack disposed over arecording unit; a radiation source configured to project radiation ontothe sheet media stack; and an imaging device that is stationary andfixed relative to the recording unit, the imaging device configured toreceive a reflection of the radiation from at least a part of the sheetmedia stack and to determine, based on the reflection, at least oneaspect of the sheet media stack.
 2. The imaging system of claim 1,wherein the imaging device is configured to determine, based on thereflection, a number of sheets in the sheet media stack.
 3. The imagingsystem of claim 1, wherein the imaging device comprises an image sensorconfigured to generate image data in response to the reflection.
 4. Theimaging system of claim 3, wherein the image sensor is selected from agroup consisting of a charge coupled device sensor and a complementarymetal-oxide semiconductor sensor.
 5. The imaging system of claim 3,wherein the radiation source is configured to project the radiation ontoa plurality of sheet media edges of the sheet media stack; and whereinthe imaging device further comprises at least one lens positioned alongan optical path between the image sensor and the plurality of sheetmedia edges.
 6. The imaging system of claim 3, wherein the radiationsource is configured to project the radiation onto a plurality of sheetmedia edges of the sheet media stack; and wherein the imaging device isconfigured to determine a number of sheets in the sheet media stack bydetecting the plurality of sheet media edges in the image data.
 7. Theimaging system of claim 6, wherein the imaging device is configured todetect the plurality of sheet media edges in the image data by:filtering the image data; and applying a threshold to the filtered imagedata to detect peaks in the filtered image data.
 8. The system of claim1, wherein the recording unit comprises a digital notepad; and whereinthe system is configured to communicate with the digital notepad.
 9. Thesystem of claim 1, wherein the sheet media stack includes paper media orplastic media.
 10. The system of claim 1, wherein the radiation sourceis configured to emit light.
 11. The system of claim 10, wherein theradiation source includes a light emitting diode or a laser diode.
 12. Amethod for imaging comprising: using an radiation source to projectradiation onto a sheet media stack disposed over a recording unit;receiving a reflection of the radiation from at least a part of thesheet media stack using an imaging device that is stationary and fixedrelative to the recording unit; and determining, based on thereflection, at least one aspect of the sheet media stack.
 13. The methodof claim 12, wherein the at least one aspect of the sheet media stack isa number of sheets in the sheet media stack.
 14. The method of claim 12,wherein the radiation is projected onto a plurality of sheet media edgesof the sheet media stack.
 15. The method of claim 14, furthercomprising: generating image data in response to the reflection of theradiation.
 16. The method of claim 15, wherein determining at least oneaspect of the sheet media stack comprises: detecting, within the imagedata, the plurality of sheet media edges of the sheet media stack. 17.The method of claim 15, wherein detecting the plurality of sheet mediaedges comprises: filtering the image data; and applying a threshold tothe filtered image data to detect peaks in the filtered image data. 18.The method of claim 12, wherein the recording unit comprises a digitalnotepad; and further comprising communicating with the digital notepad.19. The method of claim 12, wherein the radiation source is configuredto emit light.
 20. The method of claim 19, wherein the radiation sourceincludes a light emitting diode or a laser diode.